• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.12
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• pp.5028-5057
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• 2015

In this paper, a new mathematical scheme of Macro Handover Management (MHM) in F-HMIPv6 networks based on Location Based Services (LBS) is proposed. Previous schemes based on F-HMIPv6 protocol usually suffer from three major drawbacks: First, They don't exploit the information about the user mobility behavior in order to reduce handover effects. Second, they only focus on the micro mobility level. Third, they don't consider the quality of service (QoS) of the traffic. The proposed MHM scheme avoids these drawbacks using the available information about Mobile Node (MN) such as user mobility patterns and MN's velocity to predict handover and improve network's QoS. It also takes the traffic type in consideration since it presents a major factor in locating QoS for the user. MHM is analyzed and compared with the F-HMIPv6. The results show that MHM improves the performance in terms of packet delivery cost, location update cost, and handover latency. The design of MHM comprises software package in the MN in addition to a hardware part in the network side. It has implications for communication, design, and pricing of mobile services.

• The Korean Journal of Pain
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• v.27 no.2
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• pp.139-144
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• 2014

Background: To manage intractable cancer pain, an alternative to systemic analgesics is neuraxial analgesia. In long-term treatment, intrathecal administration could provide a more satisfactory pain relief with lower doses of analgesics and fewer side-effects than that of epidural administration. However, implantable drug delivery systems using intrathecal pumps in Korea are very expensive. Considering cost-effectiveness, we performed epidural analgesia as an alternative to intrathecal analgesia. Methods: We retrospectively investigated the efficacy, side effects, and complications of epidural morphine and local anesthetic administration through epidural catheters connected to a subcutaneous injection port in 29 Korean terminal cancer patients. Patient demographic data, the duration of epidural administration, preoperative numerical pain rating scales (NRS), side effects and complications related to the epidural catheterization and the drugs, and the numerical pain rating scales on the 1st, 3rd, 7th and 30th postoperative days were determined from the medical records. Results: The average score for the numerical pain rating scales for the 29 patients decreased from $7{\pm}1.0$ at baseline to $3.6{\pm}1.4$ on postoperative day 1 (P < 0.001). A similar decrease in pain intensity was maintained for 30 days (P < 0.001). Nausea and vomiting were the most frequently reported side effects of the epidural analgesia and two patients (6.9%) experienced paresthesia. Conclusions: Epidural morphine and local anesthetic infusion with a subcutaneous pump seems to have an acceptable risk-benefit ratio and allows a high degree of autonomy to patients with cancer pain.

• Journal of Korea Port Economic Association
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• v.37 no.2
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• pp.107-118
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• 2021

This study investigates the strategies that are important for selecting shuttle carriers and logistics warehouses. In container transportation, competitive pricing has become an order qualifier due to the establishment of the standard freight rate system. As a result of this study, it can be seen that both logistics warehouses and shuttle carriers place greater importance on the partnerships with companies and employee education. Besides those two factors, the punctuality of delivery is found to be important for the quality of transportation. Therefore, companies must continue to increase their competitiveness. As customer service of the shuttle carrier, resolving the loss or damage and claim handling part is evaluated more importantly in the logistics warehouse than the ablity to resolve unexpected event. The future strategy should focus on resolving the loss/damage and claim handling factors so that companies can be competitve in the future. Based on research results, logistics warehouses and shuttle carriers can establish different marketing strategies to maintain a firm position on the market by securing competitive advantage within port hinterland.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.5
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• pp.215-222
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• 1996

This paper reports on theoretical study of the compression process within balanced type vane pump for Electro-Hydraulic Power Steering(EHPS). Equations fo camring profiles are derived, then displacements, velocities, accelerations, and jerks are calculated. Vane side leakages, vane slit leakages, and rotor side leakages are considered and calculated. Numerical integration of flow equation is performed using 4th Runge-Kutta method. As a result of analysis, it is found that chamber pressure depends on rotational speeds, bulk modulus of fluid, notches, camring profiles, and positions of delivery port. Especially, the variation of notch area is the most important factor that prevents pressure from rapid rising.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1275_1276
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• 2009

Micropump is very useful component in micro/nano fluidics and bioMEMS applications. Using the flexural vibration mode of PZT bar, a piezopump is successfully made. The PZT bar is polarized with thickness direction. The proposed structure for the piezo-pump consists of an input and an output port, piezoelectric ceramic actuator, actuator support, diaphragm. The traveling flexural wave along the bar is obtained by dividing two standing waves which are temporally and spatially phase shifted by 90 degrees from each other. Fluid is drawn into a forming chamber, eventually the forming chamber closes trapping the fluid therein.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.106-114
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• 2003

The pressure ripple in the delivery port is caused by flow ripple, which is induced by variation of pumping chamber volume. The other reason is the reverse flow from the outlet volume produced by pressure difference between pumping chamber and outlet volume, when the pumping chamber is connected with the outlet volume. In this study, a mathematical model is presented for analyzing discharge pressure ripple, which includes vane detachment, cam ring movement , and fluid inertia effects in V-groove in the side plate. From the analysis and experiment, it was found that V-groove on the side plate, coefficient of spring supporting the cam ring, and average discharge pressure are the main factors of discharge pressure ripple in variable displacement vane pump. The theoretical results, provided in this study, were well agreed with experimental results. The analytical model to estimate the magnitude of pressure ripple in this study is expected to be used f3r the optimal design of the variable displacement vane pump.

• Journal of Communications and Networks
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• v.1 no.2
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• pp.134-142
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• 1999

We have developed fully functional Video Server and Client applications which can transmit, receive, decompress and display compressed video over various networks. Our video trans-port allows dynamic rate control feedback, loss detection, and repair requests from Clients to the Server. Our experiments show how feedvack-before-degradation scheme for rate adaptation maintains good display frame-rate for video playback. We show how the playback degradation(reduction in display frame-rate) oc-curs and what happens if corrective measures are not taken to im-prove the situation. The degradation is attributed to the increased internal kernel buffering which consumes scarce CPU resources. We demontrate with our experimental results that ServerNet, with improved hardware delivery guarantees, can significantly reduce host CPU resource consumption while serving video streams. We present the maximum number of streams which can be served for each of ATM and ServerNet interconnects. The appropriate user-level packet size for the video server are also determined for each case.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.1
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• pp.135-158
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• 2018

High-Speed vehicles can be considered as multiple mobile nodes that move together in a large-scale mobile network. High-speed makes the time allowed for a mobile node to complete a handover procedure shorter and more frequently. Hence, several protocols are used to manage the mobility of mobile nodes such as Network Mobility (NEMO). However, there are still some problems such as high handover latency and packet loss. So efficient handover management is needed to meet Quality of Service (QoS) requirements for real-time applications. This paper utilizes the cross-layer seamless handover technique for network mobility presented in cellular networks. It extends this technique to propose QoS-aware NEMO protocol which considers QoS requirements for real-time applications. A novel analytical framework is developed to compare the performance of the proposed protocol with basic NEMO using cost functions for realistic city mobility model. The numerical results show that QoS-aware NEMO protocol improves the performance in terms of handover latency, packet delivery cost, location update cost, and total cost.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.6
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• pp.736-744
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• 2016

Network on chip (NoC) is an emerging technology in the field of multi core interconnection architecture. The routers plays an essential components of Network on chip and responsible for packet delivery by selecting shortest path between source and destination. State-of-the-art NoC designs used routing table to find the shortest path and supports four ports for packet transfer, which consume high power consumption and degrades the system performance. In this paper, the multi port multi core router architecture is proposed to reduce the power consumption and increasing the throughput of the system. The shared buffer is employed between the multi ports of the router architecture. The performance of the proposed router is analyzed in terms of power and current consumption with conventional methods. The proposed system uses Modelsim software for simulation purposes and Xilinx Project Navigator for synthesis purposes. The proposed architecture consumes 31 mW on CPLD XC2C64A processor.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2011.10a
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• pp.61-61
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• 2011

Cavitation phenomena during the injection process of the conventional fuel injection pump for a medium-speed diesel engine can cause surface damage with material removal or round-off on the plunger and barrel port and may shorten their expected life time. An experiment of flow visualization was carried out to investigate the main cause of these cavitation damages and find the prevention method. Experimental results of flow visualization show that these damages are mainly affected by fountain-like cavitation and jet-type cavitation generated before and after the end of fuel delivery process and therefore the prevention method was designed to control these cavitation flows. From the visualization and endurance test, it was proved that this method can effectively prevent cavitation damages by controlling cavitation flows.